Just-launched price comparison engine BeatMyPrice comes from the folks who brought you BugMeNot and RetailMeNot, and puts those two services' "people-powered" ethics to good use. Here's how it works: you see an item you want to buy online at a certain price, but want to know if there are better deals out there. You enter the item name, URL, and price into BeatMyPrice.com, and hit the "Beat that!" button. BeatMyPrice lists results from various sources (including other users' searches), and includes better, the same, and higher-priced items than your entry—and it integrates coupon codes and promotions (like free shipping) from its sister site, RetailMeNot.You can narrow down the results to only the sellers and target price you want to see. Check out a video clip from the founder which shows you BeatMyPrice in action.
As I'm on the hunt for a widescreen monitor, I plugged in a couple of listings from NewEgg into BeatMyPrice, and it did find me a cheaper (albeit smaller screen) price, but the result listing was a lot sparser than the one shown in the video. As more people use BeatMyPrice, the more results it will have to offer. Right now it desperately needs a BugMeNot-style bookmarklet for use while you shop for holiday gifts online.